The present invention relates to a device and a method for measuring a moisture permeability used to measure moisture permeability features of a permeable film and other paper, cardboard, and fabric products provided in a device for removing water vapor used for dehumidification in a frame.
The moisture permeability test method for fabric products according to JIS LI099 is known as a conventional method for measuring a moisture permeability.
A method A-2 according to JIS L1099 is a water method wherein a specific amount of water is poured into a moisture permeation cup, then a specimen is formed by mounting a packing and the ring with a sample set on the moisture permeation cup.
Said specimen is stored in a specified constant temperature/humidity room, then the specimen is taken out to measure a weight after a specified time (primary measurement process) and the specimen is stored in the constant temperature/humidity room again, then the specimen is taken out to measure a weight after the specified time again (secondary measurement process).
Thereafter, a difference obtained from subtracting a value of the secondary measurement from a value of the primary measurement is converted into a moisture permeability.
Furthermore, the moisture permeability measuring device wherein the sample is clamped between an upward cup and a downward cup and temperatures and humidity of spaces in both cups are measured before and after permeation of water vapor, then, from the result of this measurement, a moisture permeability of the sample is measured in principle is known.
However, in said water method according to JIS L1099, the specimen need be taken out from the constant temperature/humidity room into the atmosphere each time the primary measurement process and the secondary measurement process is performed. Thus, the sample is much affected by an atmospheric temperature and humidity and a temperature and humidity on the surface of the sample are changed by moving wind blown onto the surface of the sample along with mounting and dismounting the specimen such that an error easily occurs in a measurement result and a reliability is poor.
Furthermore, for the moisture permeability measuring device of the latter, a measurement result greatly depends on a precision of a sensor, a measurement result differs by a sensor error at a moisture permeability measurement requiring precision, and especially, there is a problem that a measurement error caused by an aged deterioration of the sensor easily occurs.
The present invention is done to solve the above-mentioned problem, and the subject is to provide the device and method for measuring a moisture permeability comprising the steps of measuring a weight of a specimen in the constant temperature/humidity room without taking the specimen from the constant temperature/humidity room to the atmosphere without being affected by vibration and objectively evaluating the results of the weight measurement by detecting the state of the water vapor permeating a sample and the temperature of stored water.
In addition, measurements under an influence of a difference between surface temperatures of the water vapor exhaust port and the water vapor supply port of a sample and an influence of an electric charge of a sample will be enabled.
To solve the aforementioned problem, the moisture permeability measurement device according to the present invention comprises:
a precision electronic balance is installed on a damping stand (shock absorbing stand) in a constant temperature/humidity room;
low viscosity resin such as silicone or epoxy resin is permeated into a peripheral part of a measuring cup containing water;
a packing part is formed by resin such as silicon rubber or epoxy resin on the top and bottom of the peripheral part;
furthermore, the weight of a specimen in which a sample having the packing part filled with resin such as non-fluid silicone or epoxy resin covering the peripheral surface is measured by said precision electronic balance; and
the measuring cup has the cup main body with the open top and a retaining ring that clamps the sample between itself and the top of the cup main body by a specific fastening pressure; and
thermocouples immersed in water stored in the cup main body are installed through the peripheral wall part of the cup main body and a temperature-humidity sensor is installed to extend to a space between the water surface and the sample.
Moreover, a water supply and drain passage opened/closed by a valve is formed in the bottom of the cup main body and a water level drainage opened/closed by a drain valve is installed below the temperature-humidity sensor on the peripheral wall part of the cup main body.
Furthermore, the moisture permeability measurement device according to the present invention comprises:
an embodiment showing a perforated plate is installed in the vicinity of the sample on the vapor exhaust port of the sample;
another embodiment showing that said perforated plate is selected from multiple types of perforated plates having different thermal conduction speeds; and
another embodiment showing that the perforated plate is grounded.
Furthermore, the moisture permeability measuring method according to the present invention uses the moisture permeability measuring device wherein;
a specimen in which the sample is clamped between the top of the cup main body storing water and the retaining ring with a specific fastening pressure;
the specimen is installed on the precision electronic balance installed on the damping stand in the constant temperature-humidity room;
in this state, the weight of the specimen is measured for a specific time and results are converted into a moisture permeability based on a difference between a weight at the start of the measurement and a weight after the specific time is passed; and
at the same time, a water temperature is measured with the lapse of time and a temperature and humidity of a space in the specimen is measured by the temperature-humidity sensor.
Furthermore, the moisture permeability measurement method according to the present invention comprises:
an embodiment showing a moisture permeability is measured with or without a perforated plate installed in the vicinity of the sample on the vapor exhaust port of the sample; and
furthermore, another embodiment shows that a moisture permeability is measured with or without a perforated plate grounded.